Nature of problem:The soliton bag model for QCD is a covariant field theory described by
a complete Hamiltonian. The model is sufficiently general to describe
either the MIT or SLAC bags by suitable limits of the parameters which
determine the soliton field. Mathematically, the model consists of a
nonlinear second order ordinary differential equation coupled with an
eigenvalue problem for a coupled system of linear first order ordinary
differential equations. The physical quantities calculated from the
solutions of the differential equations are the rms charge radius,
recoil corrected rms charge radius, bag energy, mean square momentum,
recoil corrected bag mass, static magnetic moment, recoil corrected
magnetic moment, and the axial-vector coupling constant.

Solution method:The algorithm can be briefly described as follows:
Step 1: Choose an initial estimate for the soliton field.
Step 2: Using the current estimate for the soliton field, solve the
eigenvalue problem, i.e. the Dirac wave function for the s1/2
state.
Step 3: Check for convergence of the soliton field, eigenvalue, and
eigenfunctions. If the solutions have converged then proceed
to step 5, otherwise continue to step 4.
Step 4: Using the current wave function, solve the nonlinear
differential equation for the soliton field. The algorithm
continues at step 2 using the new estimate of soliton field.
Each completion of step 4 is called a cycle.
Step 5: If the number of constituents of the bag is three (i.e. a
nucleon) and the recoil corrected rms charge radius exceeds
.83 fm by some preassigned tolerance, then scale the length so
that the recoil corrected rms charge radius .83 fm, scale the
soliton field, eigenvalue, and the adjustable parameters so
that the scaled soliton field and scaled eigenvalue is a
solution of the mathematical model with scaled adjustable
parameters and repeat starting at step 2. Otherwise continue
to step 6. For measons no rescaling is done.
Step 6: Calculate the quantities of physical interest.